From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S268840AbUHUDo1 (ORCPT ); Fri, 20 Aug 2004 23:44:27 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S268841AbUHUDo1 (ORCPT ); Fri, 20 Aug 2004 23:44:27 -0400 Received: from mustang.oldcity.dca.net ([216.158.38.3]:28873 "HELO mustang.oldcity.dca.net") by vger.kernel.org with SMTP id S268840AbUHUDn7 (ORCPT ); Fri, 20 Aug 2004 23:43:59 -0400 Subject: Re: [patch] voluntary-preempt-2.6.8.1-P6 From: Lee Revell To: Ingo Molnar Cc: linux-kernel , Thomas Charbonnel , Florian Schmidt , Felipe Alfaro Solana , Mark_H_Johnson@raytheon.com In-Reply-To: <20040820195540.GA31798@elte.hu> References: <20040816034618.GA13063@elte.hu> <1092628493.810.3.camel@krustophenia.net> <20040816040515.GA13665@elte.hu> <1092654819.5057.18.camel@localhost> <20040816113131.GA30527@elte.hu> <20040816120933.GA4211@elte.hu> <1092716644.876.1.camel@krustophenia.net> <20040817080512.GA1649@elte.hu> <20040819073247.GA1798@elte.hu> <20040820133031.GA13105@elte.hu> <20040820195540.GA31798@elte.hu> Content-Type: text/plain Message-Id: <1093059838.854.11.camel@krustophenia.net> Mime-Version: 1.0 X-Mailer: Ximian Evolution 1.4.6 Date: Fri, 20 Aug 2004 23:43:59 -0400 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 2004-08-20 at 15:55, Ingo Molnar wrote: > i've uploaded the -P6 patch: > > http://redhat.com/~mingo/voluntary-preempt/voluntary-preempt-2.6.8.1-P6 > Here's a 171 usec latency from ext3_free_blocks: preemption latency trace v1.0.1 ------------------------------- latency: 171 us, entries: 2 (2) ----------------- | task: evolution/863, uid:1000 nice:0 policy:0 rt_prio:0 ----------------- => started at: ext3_free_blocks+0x1d0/0x4b0 => ended at: ext3_free_blocks+0x229/0x4b0 =======> 00000001 0.000ms (+0.000ms): ext3_free_blocks (ext3_free_data) 00000001 0.167ms (+0.167ms): sub_preempt_count (ext3_free_blocks) Also I have noticed a pattern with the XFree86 schedule() latencies, they all have a section like this: 04000002 0.003ms (+0.000ms): effective_prio (recalc_task_prio) 04000002 0.003ms (+0.000ms): enqueue_task (schedule) 00000002 0.006ms (+0.003ms): __switch_to (schedule) 00000002 0.088ms (+0.082ms): finish_task_switch (schedule) 00010002 0.090ms (+0.001ms): do_IRQ (finish_task_switch) 00010003 0.091ms (+0.000ms): mask_and_ack_8259A (do_IRQ) 04000002 0.002ms (+0.000ms): effective_prio (recalc_task_prio) 04000002 0.002ms (+0.000ms): enqueue_task (schedule) 00000002 0.005ms (+0.002ms): __switch_to (schedule) 00000002 0.067ms (+0.062ms): finish_task_switch (schedule) 00010002 0.068ms (+0.001ms): do_IRQ (finish_task_switch) 00010003 0.069ms (+0.000ms): mask_and_ack_8259A (do_IRQ) I presume the 04000002 -> 00000002 is some interrupt being unmasked (or interrupts being globally enabled), then there's a 60-80 usec latency in schedule(). Lee